Hi, Ive Had A Cold Sore For About A Week

Hi, ive had a cold sore for about a week that is finally starting to go away. Out of nowhere, there is a bump under it which looks like another cold sore is about to pop out. Is there any way I can stop it at this stage? Is there any medication my doctor could prescribe to make it go away asap? If so, what is it? Please help!